Polymeric micelles are frequently used to transport and deliver drugs throughout the body because they protect against degradation. Research on functional polymeric micelles for biomedical applications has generally shown that micelles have beneficial properties, such as specific functionality, enhanced specific tumor targeting, and stabilized nanostructures. The particular aim of this study was to synthesize and characterize multifunctional polymeric micelles for use in controlled drug delivery systems and biomedical imaging. In this study, a theranostic agent, doxorubicin/superparamagnetic iron oxide (SPIO)-encapsulated Pluronic F127 (F127) micelles, was developed for dual chemotherapy/magnetic resonance imaging (MRI) purposes, and the structure and composition of the micellar SPIO were characterized by transmission electron microscopy and magnetic measurements. Our results revealed that the micellar SPIO with a diameter of around 100 nm led to a significant advantage in terms of T2 relaxation as compared with a commercial SPIO contrast agent (Resovist (R)) without cell toxicity. After doxorubicin encapsulation, a dose-dependent darkening of MR images was observed and HeLa cells were killed by this theranostic micelle. These findings demonstrate that F127 micelles containing chemotherapeutic agents and SPIO could be used as a multifunctional nanocarrier for cancer treatment and imaging. (c) 2010 American Institute of Physics. [doi:10.1063/1.3357344]